The following example confines the cursor to the application's window and then restores the cursor to its previous window. The example uses the GetClipCursor function to record the area in which the cursor can move and the ClipCursor function to confine and restore the cursor.
RECT rcClip; // new area for ClipCursor
RECT rcOldClip; // previous area for ClipCursor
// Record the area in which the cursor can move.
GetClipCursor(&rcOldClip);
// Get the dimensions of the application's window.
GetWindowRect(hwnd, &rcClip);
// Confine the cursor to the application's window.
ClipCursor(&rcClip);
//
// Process input from the confined cursor.
//
// Restore the cursor to its previous area.
ClipCursor(&rcOldClip);
Because there is only one cursor at a time available in the system, an application that confines the cursor must restore the cursor before relinquishing control to another window.